1. Field of the Invention
The invention relates generally to gun sight alignment apparatus and, more particularly, but not by way of limitation, it relates to an improved sighting device utilizing a bore-aligned light beam for calibration adjustment of mechanical and microscopic gun sights.
2. Description of the Prior Art
The prior art includes numerous types of sight calibration device for aligning a gun sight in true relationship with the gun bore. Early procedures for bore alignment included various means for aligning the bore axis at or near the end of the muzzle with the sight axis, and with additional means for allowance of bullet drop per distance. Later attempts at sighting in of rifles included various light projection devices which enabled somewhat more precise alignment. U.S. Pat. Nos. 4,168,429 and 3,787,693 were directed to infrared bore scope devices which enabled alignment in the field without the necessity for firing a shot. The '693 patent actually uses a light emitting device that is held in alignment with the bore axis for target reflection and subsequent viewing by the operator having a night viewing scope on his head. This device requires alignment of a pulsing and a continuous beam in order to align the rifle sight.
U.S. Pat. No. 3,711,204 teaches another type of device which is inserted in the muzzle end of the gun bore to prove alignment. This device utilizes a reverting optical means for use in initial centering of the device on the axis of the gun barrel and, thereafter, the device is tightly secured for subsequent viewing and alignment by means of the rifle sight. U.S. Pat. No. 4,530,162 teaches a different approach wherein a light source is employed to direct a beam of light from the breech through the barrel bore to a distant target, whereupon the optical sight or scope may be adjusted relative to the spot. U.S. Pat. No. 3,782,832 teaches a similar type of device wherein a light emitting source is formed in the general shape of a cartridge and it is inserted in the breech of the weapon to provide a narrow bore sight light along the true bore axis of the weapon. The weapon also carries a scope-like aiming light which may be aligned with the bore axis light to assure correct sighting for nighttime firing. Still other patents of less pertinence are noted in the Information Disclosure Statement submitted herewith.